U.S. patent application number 13/475611 was filed with the patent office on 2013-11-21 for process for preparing catalysts and catalysts made thereby.
This patent application is currently assigned to UNION CARBIDE CHEMICALS & PLASTICS TECHNOLOGY LLC. The applicant listed for this patent is Robert James Jorgensen. Invention is credited to Robert James Jorgensen.
Application Number | 20130310526 13/475611 |
Document ID | / |
Family ID | 47997953 |
Filed Date | 2013-11-21 |
United States Patent
Application |
20130310526 |
Kind Code |
A1 |
Jorgensen; Robert James |
November 21, 2013 |
Process for Preparing Catalysts and Catalysts made thereby
Abstract
A process for preparing a catalyst, and catalysts prepared
thereby. The process includes selecting a catalyst support and
mixing it with one or more chromium containing compounds oxidizable
to a Cr.sup.+6 state or already in a Cr.sup.+6 state, and with with
one or more transition metal catalyst component, and calcining the
catalyst support while oxidizing any chromium containing compound
to a Cr.sup.+6 state, and spray drying the catalyst support to form
catalyst particles. The catalyst supports are characterized by a
surface area greater than 50 m.sup.2/gram and a pore volume greater
than 0.5 cc/gram at the time of mixing the catalyst support gels
with the chromium containing compound.
Inventors: |
Jorgensen; Robert James;
(Scott Depot, WV) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jorgensen; Robert James |
Scott Depot |
WV |
US |
|
|
Assignee: |
UNION CARBIDE CHEMICALS &
PLASTICS TECHNOLOGY LLC
Midland
MI
|
Family ID: |
47997953 |
Appl. No.: |
13/475611 |
Filed: |
May 18, 2012 |
Current U.S.
Class: |
526/106 ;
502/107; 502/159; 502/210; 502/256; 502/320 |
Current CPC
Class: |
B01J 37/04 20130101;
B01J 35/1042 20130101; C08F 4/63912 20130101; C08F 10/00 20130101;
C08F 10/00 20130101; C08F 10/02 20130101; C08F 10/00 20130101; B01J
35/023 20130101; B01J 37/0045 20130101; C08F 4/659 20130101; B01J
35/1014 20130101; C08F 4/69 20130101; C08F 4/63925 20130101; B01J
37/12 20130101; B01J 37/0201 20130101; C08F 4/64148 20130101; C08F
10/00 20130101; C08F 4/63904 20130101; C08F 4/025 20130101; C08F
4/65925 20130101; C08F 4/69 20130101; C08F 10/00 20130101; B01J
31/2295 20130101; B01J 23/26 20130101 |
Class at
Publication: |
526/106 ;
502/256; 502/320; 502/210; 502/159; 502/107 |
International
Class: |
C08F 4/24 20060101
C08F004/24; C08F 4/69 20060101 C08F004/69; C08F 10/02 20060101
C08F010/02 |
Claims
1. A process for preparing a catalyst comprising: (A) selecting a
catalyst support selected from the group consisting of gels of
silica, silica alumina, alumina, aluminum phosphate,
aluminaphosphate, and combinations of two or more thereof; (B)
mixing the catalyst support with one or more chromium containing
compound, wherein the chromium containing compound is selected from
the group consisting of chromium containing compounds which are
oxidizable to a Cr.sup.+6 state and chromium containing compounds
wherein the chromium is in a Cr.sup.+6 state; (C) mixing the
catalyst support with one or more transition metal catalyst
component; (D) calcining the catalyst support while continuously
agitating to prevent agglomeration; (E) optionally for the chromium
containing compound which is oxidizable to a Cr.sup.+6 state,
converting the chromium in the chromium containing compound to
Cr.sup.+6; and (F) spray drying the catalyst support to form
catalyst particles; wherein steps (B)-(F) may occur separately in
any order or wherein any one or more of steps (B)-(F) may be
combined together; and wherein the catalyst support gels are
characterized by a surface area greater than 50 m.sup.2/gram and a
pore volume greater than 0.5 cc/gram at the time of mixing the
catalyst support gels with the chromium containing compound.
2. The process according to claim 1, wherein steps (B) and (D) are
conducted sequentially.
3. The process according to claim 1, wherein step (B) occurs prior
to steps (C)-(F) and steps (D) and (E) occur simultaneously.
4. The process according to claim 1, wherein the catalyst support
selected in step (A) comprises gels larger than 50 micron
characterized by a surface area greater than 50 m.sup.2/gram and a
pore volume greater than 0.5 cc/gram, and wherein step (D) occurs
following step (A) and is followed by comminution of the catalyst
support gels to form gels characterized by a surface area greater
than 50 m.sup.2/gram and a pore volume greater than 0.5 cc/gram
prior to step (B) and an average particle size less than 15
micron.
5. The process according to claim 1, wherein steps (A), (B) and (D)
occur in order to form a chromium compound impregnated, calcined
catalyst support gels, and further comprising suspension of the
chromium compound impregnated, calcined catalyst support gels in a
solvent containing a binder to form a suspension.
6. The process according to claim 5, wherein the binder is selected
from the group consisting of methylalumoxane, polystyrene,
polystyrene-ethylene copolymers, polysytrene allyl alcohol
copolymers, polyvinylchloride, polyisoprene, polybutadiene,
partially hydrogenated polyisoprene, modified methylalumoxane,
polyvinylacetate, isobutylalumoxane, and trialkylaluminum compounds
having the formula AlR.sub.3 where R is a saturated alkyl group
having more than 12 carbons and is soluble in aromatic
solvents.
7. The process according to claim 1, wherein the chromium
containing compound is selected from bis(triarylsilyl)chromates,
and compounds characterized by the formula R.sup.b.sub.2Cr where
R.sup.b is a substituted or unsubstituted indenyl or
cyclopentadienyl and wherein the two R.sup.b may be the same or
different.
8. The process according to claim 1, wherein the chromium
containing compound is selected from the group consisting of
chromium containing compounds having a Cr+3 state which are water
and/or alcohol soluble.
9. The process according to claim 1, wherein the chromium
containing compound is characterized by the formula
Cr(NO.sub.3).sub.3 and/or the formula Cr(CO.sub.2).sub.3.
10. The process according to claim 1, wherein the chromium
containing compound is bis(triphenylsilyl)chromate.
11. The process according to claim 1, wherein the chromium
containing compound is selected from the group consisting of
bis-cyclopentadienylchromium, bis-indenylchromium,
bis-pentamethycyclopentadienylchromium, and combinations of two or
more thereof
12. The process according to claim 1, wherein step (F) results in
particles having a particle size of greater than 5 microns.
13. The process according to claim 12, wherein the resulting
particles have a (volume or weight average) particle size of from
10 to 75 microns.
14. The process according to claim 12, wherein the resulting
particles have a (volume or weight average) particle size of from 5
to 59 microns.
15. The process according to claim 13, further comprising
polymerizing ethylene and optionally one or more co-monomers in the
presence the catalyst particles in a gas phase fluidized bed.
16. The process according to claim 14, further comprising
polymerizing ethylene and optionally one or more co-monomers in the
presence of the catalyst particles which have been suspended in
mineral oil, said polymerizing occurring in a slurry reaction
system.
Description
FIELD OF INVENTION
[0001] The instant invention relates to a process for preparing
catalysts and catalysts made by such process.
BACKGROUND OF THE INVENTION
[0002] Existing processes for the production of multi-modal
polyethylene typically rely on two or more polymerization reactors
operating at different reaction conditions. Generally, in a
two-reactor in series systems, catalyst is fed only to the first
reactor in the series so that the polymer particles eventually
produced are of more homogeneous composition, i.e. so that all
particles contain polymer produced in both reactors. In continuous
reactions systems, however, there always exists some level of
polymer bypass (i.e. from one reactor into the next) such that all
polymer particles do not have the same residence time in each of
the two reactors. This may result in formation of polymer gels and
non-homogeneous particles which may be difficult to melt process.
Additionally, matching production rates in two (or more) reactors
may be complicated due to catalyst decay and may also lead to
polymer inhomogeneity. Further, in order to provide a broad
molecular weight distribution, the individual polymer components
produced in each reactor are frequently made to have different
molecular weight peaks, leading to a "valley" in the molecular
weight distribution of the final overall polymer product.
SUMMARY OF THE INVENTION
[0003] The instant invention is a process for producing a catalyst
and catalyst made using such process.
[0004] In one embodiment, the instant invention provides a process
for preparing a catalyst comprising (A) selecting a catalyst
support from the group consisting of gels of silica, silica
alumina, alumina, aluminum phosphate, aluminaphospate, and
combinations of two or more thereof; (B) mixing the catalyst
support with one or more chromium containing compound, wherein the
chromium containing compound is selected from the group consisting
of chromium containing compounds which are oxidizable to a
Cr.sup.|6 state and chromium containing compounds wherein the
chromium is in a Cr.sup.+6 state; (C) mixing the catalyst support
with one or more transition metal catalyst component; (D) calcining
the catalyst support; and (E) optionally for the chromium
containing compound which is oxidizable to a Cr.sup.+6 state,
converting the chromium in the chromium containing compound to
Cr.sup.+6; and (F) spray drying the catalyst support to form
catalyst particles; wherein steps (B)-(F) may occur separately in
any order or wherein any one or more of steps (B)-(F) may be
combined together; and wherein the catalyst support gels are
characterized by a surface area greater than 50 m.sup.2/gram and a
pore volume greater than 0.5 cc/gram at the time of mixing the
catalyst support gels with the chromium containing compound.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] For the purpose of illustrating the invention, there is
shown in the drawings a form that is exemplary; it being
understood, however, that this invention is not limited to the
precise arrangements and instrumentalities shown.
[0006] FIG. 1 is a size exclusion chromatograph for polymers
produced using Catalyst Example 7 and by a silyl chromate
catalyst.
DETAILED DESCRIPTION OF THE INVENTION
[0007] The instant invention is a process for preparing a catalyst
and catalysts made thereby. The process for preparing a catalyst
according to the present invention comprises: (A) selecting a
catalyst support gel from the group consisting of gels of silica,
silica alumina, alumina, aluminum phosphate, aluminaphospate, and
combinations of two or more thereof; (B) mixing the catalyst
support gel with one or more chromium containing compounds, wherein
the chromium containing compound is selected from the group
consisting of chromium containing compounds which are oxidizable to
a Cr.sup.+6 state and chromium containing compounds wherein the
chromium is in a Cr.sup.+6 state; (C) mixing the catalyst support
gel with one or more transition metal catalyst components (D)
calcining the catalyst support gel; and (E) optionally for the
chromium containing compound which is oxidizable to a Cr.sup.+6
state, converting the chromium in the chromium containing compound
to Cr.sup.+6; and (F) spray drying the catalyst support gel to form
catalyst particles; wherein steps (B)-(F) may occur separately in
any order or wherein any one or more of steps (B)-(F) may be
combined together; and wherein the catalyst support gels are
characterized by a surface area greater than 50 m.sup.2/gram and a
pore volume greater than 0.5 cc/gram at the time of mixing the
catalyst support gels with the chromium containing compound.
[0008] In another embodiment, the instant invention provides a
catalyst prepared in accordance with any of the embodiments of the
process disclosed herein.
[0009] In a particular embodiment, the process to prepare a
catalyst comprises (a) calcining a catalyst particle gel selected
from the group consisting of gels of silica, silica alumina,
alumina, aluminum phosphate, aluminaphosphate, and combinations of
two or more thereof and characterized by a surface area greater
than 50 m.sup.2/gram and a pore volume greater than 0.5 cc/gram;
(b) forming a suspension of the calcined catalyst support gel and
an organochromate compound, such as bis(triphenylsilyl)chromate, in
a suitable solvent; and (c) spray drying the suspension with a
reducing agent for the chromate, wherein the reducing agent is
selected from the group of methylalumoxane (MAO), modified
methylalumoxane (MMAO), and AlR.sub.3 where R is a hydrocarbon
alkyl group having 8 or more carbon atoms.
[0010] In a particular embodiment, the process to prepare a
catalyst comprises (a) mixing a chromium containing compound
oxidizable to Cr.sup.+6 with one or more catalyst support gels
selected from the group consisting of silica, alumina, aluminum
phosphate, silica alumina and aluminophosphate, wherein the
catalyst support gel is characterized by a surface area greater
than 50 m.sup.2/gram and a pore volume greater than 0.5 cc/gram, to
form a chromium impregnated catalyst support gel; (b) calcining the
chromium impregnated catalyst support gel with an oxygen containing
atmosphere to convert the chromium to Cr.sup.+6 at a temperature
between 350.degree. C. to the sintering temperature of the catalyst
support gel; (c) suspending the calcined chromium containing
catalyst support gel in a solvent with one or more binders selected
from the group of polymers which are soluble in said solvent and
which are non-reactive to the Cr.sup.+6 species, MAO,
isobutylalumoxane and trialkylaluminum compounds wherein the alkyl
group has 8 or more carbon atoms to form a suspension; and (d)
spray drying the suspension.
[0011] In a particular embodiment, the process to prepare a
catalyst comprises (a) calcining a catalyst particle gel selected
from the group consisting of gels of silica, silica alumina,
alumina, aluminum phosphate, aluminaphosphate, and combinations of
two or more thereof; (b) comminuting the catalyst particle gel to
achieve a gel characterized by a surface area greater than 50
m.sup.2/gram and a pore volume greater than 0.5 cc/gram; (c)
forming a suspension of the calcined catalyst support gel and an
organochromate compound, such as bis(triphenylsilyl)chromate, in a
suitable solvent; and (d) spray drying the suspension with a
reducing agent for the chromate, wherein the reducing agent is
selected from the group of methylalumoxane (MAO), modified
methylalumoxane (MMAO), and AlR.sub.3 where R is a hydrocarbon
radical having 8 or more carbon atoms.
[0012] In yet another embodiment, the process to prepare a catalyst
comprises (a) mixing a chromium containing compound oxidizable to
Cr.sup.+6 with one or more catalyst support gels selected from the
group consisting of silica, alumina, aluminum phosphate, silica
alumina and aluminophosphate, to form a chromium impregnated
catalyst support gel; (b) calcining the chromium impregnated
catalyst support gel with an oxygen containing atmosphere to
convert the chromium to Cr.sup.+6 at a temperature between
350.degree. C. to the sintering temperature of the catalyst support
gel; (c) comminuting the calcined catalyst support gel to achieve a
gel characterized by a surface area greater than 50 m.sup.2/gram
and a pore volume greater than 0.5 cc/gram, (d)suspending the
calcined chromium containing catalyst support gel in a solvent with
one or more binders selected from the group of polymers which are
soluble in said solvent and which are non-reactive to the Cr-.sup.6
species, MAO, isobutylalumoxane and trialkylaluminum compounds
wherein the alkyl group has 8 or more carbon atoms to form a
suspension; and (e) spray drying the suspension.
[0013] In yet another embodiment, the process to prepare a catalyst
comprises (a) mixing a chromium containing compound oxidizable to
Cr.sup.+6 with one or more catalyst support gels selected from the
group consisting of silica, alumina, aluminum phosphate, silica
alumina and aluminophosphate characterized by a surface area
greater than 50 m.sup.2/gram and a pore volume greater than 0.5
cc/gram to form a chromium containing catalyst support gel; (b)
calcining the chromium containing catalyst support gel in an oxygen
containing atmosphere to convert the chromium to Cr.sup.+6 state;
(c) suspending the calcined chromium containing catalyst support
gel in a solvent containing one or more binders, wherein the one or
more binders is selected from the group consisting of polymers
soluble in said solvent which are non-reactive to the Cr.sup.+6
species, MAO, isobutylalumoxane (IBAO), trialkylaluminum compounds
wherein the alkyl has 8 or more carbon atoms, to form a suspension;
(d) adding to the suspension at least one transition metal
component which is activatable by MAO or IBAO; (e) adding MAO or
IBAO to the suspension; and (f) spray drying the suspension.
[0014] In yet another embodiment, the process to prepare a catalyst
comprises (a) calcining a catalyst particle gel selected from the
group consisting of gels of silica, silica alumina, alumina,
aluminum phosphate, aluminaphosphate, and combinations of two or
more thereof and characterized by a surface area greater than 50
m.sup.2/gram and a pore volume greater than 0.5 cc/gram; (b)
suspending the calcined catalyst support gel in a solvent to form a
suspension; (c) adding silyl chromate to the suspension; (d) adding
one or more binders selected from the group consisting of polymers
soluble in said solvent which are non-reactive to the Cr.sup.+6
species, MAO, IBAO, trialkylaluminum compounds wherein the alkyl
has 8 or more carbon atoms to the suspension; (e) adding to the
suspension MAO and/or IBAO unless already added in step (d); (f)
spray drying the suspension.
[0015] In yet another embodiment, the process to prepare a catalyst
comprises (a) mixing a chromium containing compound oxidizable to
Cr.sup.+6 with one or more catalyst support gels selected from the
group consisting of gels of silica, silica alumina, alumina,
aluminum phosphate, aluminaphosphate, and combinations of two or
more thereof and characterized by a surface area greater than 50
m.sup.2/gram and a pore volume greater than 0.5 cc/gram to form a
chromium containing catalyst support gel; (b) calcining the
chromium containing catalyst support gel in an oxygen containing
atmosphere to convert the chromium to a Cr.sup.+6 state; (c)
suspending the calcined product in a solvent containing one or more
binders selected from the group consisting of polymers soluble in
said solvent which are non-reactive to the Cr.sup.|6 species, MAO,
IBAO, trialkylaluminum compounds wherein the alkyl has 8 or more
carbon atoms to form a suspension; (d) adding to the suspension at
least one transition metal component which self supports on the
catalyst support gel; (e) adding to the suspension MAO and/or IBAO
to unless added in step (c); (f) spray drying the suspension.
[0016] In yet another embodiment, the process to prepare a catalyst
comprises (a) mixing a chromium containing compound oxidizable to
Cr.sup.+6 with one or more catalyst support gels selected from the
group consisting of gels of silica, silica alumina, alumina,
aluminum phosphate, aluminaphosphate, and combinations of two or
more thereof and characterized by a surface area greater than 50
m.sup.2/gram and a pore volume greater than 0.5 cc/gram to form a
chromium containing catalyst support gel; (b) calcining the
chromium containing catalyst support gel in an oxygen containing
atmosphere to convert the chromium to a Cr.sup.+6 state; (c)
suspending the calcined product in a solvent to form a suspension;
(d) adding to the suspension a slurry formed by (i) calcining one
or more catalyst support gels characterized by a surface area
greater than 50 m.sup.2/gram and a pore volume greater than 0.5
cc/gram; (ii) suspending the calcined product of step (d) (i) in a
solvent; and (iii) adding silyl chromate to form a slurry; (e)
adding to the suspension one or more binders selected from the
group consisting of polymers soluble in said solvent which are
non-reactive to the Cr.sup.+6 species, MAO, IBAO and
trialkylaluminum compounds where the alkyl has 8 or more carbon
atoms; (f) adding to the suspension MAO, MMAO or IBAO if not added
in step (e); (g) adding to the suspension a transition metal
component that is activatable by MAO or IBAO; and (h) spray drying
the suspension.
[0017] In yet another embodiment, the process to prepare a catalyst
comprises (a) mixing a chromium containing compound oxidizable to
Cr.sup.+6 with one or more catalyst support gels selected from the
group consisting of silica, alumina, aluminum phosphate, silica
alumina and aluminophosphate, wherein the catalyst support gel is
characterized by a surface area greater than 50 m.sup.2/gram and a
pore volume greater than 0.5 cc/gram, to form a chromium containing
catalyst support gel; (b) calcining the chromium containing
catalyst support gel in oxygen containing atmosphere to convert the
chromium to a Cr.sup.+6 state; (c) suspending the calcined product
in a solvent to form a suspension; (d) adding to the suspension a
slurry formed b: (i) mixing a chromium containing compound
oxidizable to Cr.sup.+6 with one or more catalyst support gels
selected from the group consisting of silica, alumina, aluminum
phosphate, silica alumina and aluminophosphate, wherein the
catalyst support gel is characterized by a surface area greater
than 50 m.sup.2/gram and a pore volume greater than 0.5 cc/gram, to
form a chromium containing catalyst support gel; (ii) calcining the
chromium containing catalyst support gel in an oxygen containing
atmosphere to convert the chromium to a Cr.sup.+6 state; (iii)
suspending the calcined product in a solvent containing one or more
binders selected from the group consisting of polymers soluble in
said solvent which are non-reactive to the Cr.sup.+6 species, MAO,
IBAO and trialkylaluminum compounds where the alkyl group has 8 or
more carbon atoms; and (iv) adding to the suspension at least one
transition metal component which is activated by MAO or IBAO; (e)
adding to the suspension one or more binders selected from the
group consisting of polymers soluble in said solvent which are
non-reactive to the Cr.sup.+6 species, MAO, IBAO and
trialkylaluminum compounds where the alkyl group has 8 or more
carbon atoms; and (f) spray drying the suspension.
[0018] In yet another embodiment, the process to prepare a catalyst
comprises (a) calcining one or more catalyst support gels selected
from the group consisting of silica, alumina, aluminum phosphate,
silica alumina and aluminophosphate, wherein the catalyst support
gel is characterized by a surface area greater than 50 m.sup.2/gram
and a pore volume greater than 0.5 cc/gram; (b) suspending the
calcined support gel in a solvent to form a suspension; (c) adding
to and reaction with the suspension a cationic activator capable of
activating metallocene and non-metallocene type catalysts (as
defined in U.S. Pat. No. 6,825,287, incorporated herein by
reference); (d) adding a solvent containing one or more binders
selected from the group consisting of polymers soluble in said
solvent which are non-reactive to the Cr.sup.+6 species, MAO, IBAO
and trialkylaluminum compounds where the alkyl group has 8 or more
carbon atoms; (e) adding a metallocene and/or non-metallocene
catalyst activatable by the cationic activator added in step (c);
(f) adding MAO or IBAO to the suspension unless already added in
step (d); (g) spray drying the suspension.
[0019] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby, in
accordance with any of the preceding embodiments, except that the
process further comprises dispersing the spray dried catalyst
particles into a mineral oil slurry for catalyst feed in a
polymerization reactor.
[0020] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby, in
accordance with any of the preceding embodiments, except that the
process further comprises using the spray dried catalyst particles
as a dry powder for catalyst feed in a polymerization reactor.
[0021] In another alternative embodiment, the instant invention
provides a process for preparing a catalyst and a catalyst made
thereby wherein the process consists essentially of: (A) selecting
a catalyst support gel from the group consisting of gels of silica,
silica alumina, alumina, aluminum phosphate, aluminaphosphate, and
combinations of two or more thereof; (B) mixing the catalyst
support gel with one or more chromium containing compound, wherein
the chromium containing compound is selected from the group
consisting of chromium containing compounds which are oxidizable to
a Cr.sup.+6 state and chromium containing compounds wherein the
chromium is in a Cr.sup.+6 state; (C) mixing the catalyst support
gel with one or more transition metal catalyst components (D)
calcining the catalyst support gel; and (E) optionally for the
chromium containing compound which is oxidizable to a Cr.sup.+6
state, converting the chromium in the chromium containing compound
to Cr.sup.+6; and (F) spray drying the catalyst support gel to form
catalyst particles; wherein steps (B)-(F) may occur separately in
any order or wherein any one or more of steps (B)-(F) may be
combined together; and wherein the catalyst support gels are
characterized by a surface area greater than 50 m.sup.2/gram and a
pore volume greater than 0.5 cc/gram at the time of mixing the
catalyst support gels with the chromium containing compound.
Catalyst Support Gels
[0022] Embodiments of the process utilize catalyst support gels
characterized by a surface area greater than 50 m.sup.2/gram at the
time of mixing the catalyst support gels with the chromium
containing compound. All values and subranges from greater than 50
m.sup.2/gram are included herein and disclosed herein. For example,
the catalyst support gels may have a surface area greater than 50
m.sup.2/gram; or in the alternative, the catalyst support gels may
have a surface area greater than 75 m.sup.2/gram; or in the
alternative, the catalyst support gels may have a surface area
greater than 100 m.sup.2/gram. In alternative embodiments, the
catalyst support gels may have a surface area from greater than 50
m.sup.2/gram to 75 m.sup.2/gram, or in the alternative, from 60
m.sup.2/gram to 80 m.sup.2/gram, or in the alternative, from 100
m.sup.2/gram to 200 m.sup.2/gram, or in the alternative, from 150
m.sup.2/gram to 350 m.sup.2/gram, or in the alternative, from 200
m.sup.2/gram to 325 m.sup.2/gram, or in the alternative, from 250
m.sup.2/gram to 350 m.sup.2/gram.
[0023] Embodiments of the process utilize catalyst support gels
characterized by a pore volume greater than 0.5 cc/gram at the time
of mixing the catalyst support gels with the chromium containing
compound. All individual values and subranges of greater than 0.5
cc/gram are included herein and disclosed herein. For example, the
catalyst support gels may be characterized by a pore volume greater
than 0.5 cc/gram; or in the alternative, the catalyst support gels
may be characterized by a pore volume greater than 0.65 cc/gram; or
in the alternative, the catalyst support gels may be characterized
by a pore volume greater than 0.8 cc/gram. In alternative
embodiments, the catalyst support gels may be characterized by a
pore volume from greater than 0.5 cc/gram to 1.1 cc/gram; or in the
alternative, from 0.6 cc/gram to 0.8 cc/gram.
[0024] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby, in
accordance with any of the preceding embodiments, except that
catalyst support gels are characterized by a thermal stability up
to 600.degree. C. with certain of the catalyst support gels
exhibiting thermal stability to as high as 900.degree. C. All
individual values and subranges of up to 600.degree. C. are
included herein and disclosed herein. For example, the thermal
stability of the catalyst support gels may be to an upper limit of
500, 525, 550, 575 or 600.degree. C. As used herein, the term
"thermal stability" means that the catalyst support gel exhibits
less than 5% change in surface area or pore volume.
[0025] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby, in
accordance with any of the preceding embodiments, except that
catalyst support gels are characterized by a particle size,
D.sub.90, of less than 15 microns. All individual values and
subranges of less than 15 microns are included herein and disclosed
herein. For example, the particle size, D.sub.90, may be from an
upper limit of 15, 14, 13, 12, 11, 10, 9 or 8 microns.
[0026] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby, in
accordance with any of the preceding embodiments, except that
catalyst support gels are characterized by a particle size,
D.sub.10, of greater than0.5 micron. All individual values and
subranges of greater than 0.5 micron are included herein and
disclosed herein. For example, the particle size, D.sub.10, may be
from a lower limit of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, or 1.1
microns.
[0027] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except that the
catalyst support gel has a larger particle size which is
comminuted, either before or after the thermal treatment and/or Cr
compound deposition.
[0028] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except that the
catalyst support gel acts as both a support for the active catalyst
metal, i.e., chromium, and an integral part of the catalyst
composition.
Chromium Containing Compounds
[0029] Chromium containing compounds useful in embodiments of the
invention are chromium containing compounds supported on a catalyst
support gel (in accordance with embodiments of the invention)
wherein the chromium-containing compound comprises a chromium which
is oxidizable to a Cr.sup.+6 valence state (or "state"). With such
chromium oxide type compounds, the oxidation may occur in a
calcination step. The oxidized chromium containing compound (i.e.
in the Cr.sup.+6 state) oxide may be subsequently reducible by
chemical means to the active polymerization catalyst, either prior
to introduction to the polymerization reactor or in the
polymerization reactor
[0030] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except that a
supported chromium oxide type catalyst is used and that the
catalyst includes a titanate promoter. Such titanate promoter may
be included in the catalyst support gel during catalyst support gel
manufacture or added separately during a chromium deposition step
(e.g., step (B) of mixing the chromium containing compound with the
catalyst support gel) or during the thermal treatment. In yet an
alternative embodiment, titanate promoter may be added during both
a chromium deposition step and during thermal treatment.
[0031] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except that the
chromium containing compound is characterized by the formula
(R.sup.aO).sub.2CrO.sub.2 where R.sup.a is a silyl group or an
organic ester. Exemplary chromium containing compounds include the
bis(triarylsilyl)chromates, such as
bis(triphenylsilyl)chromate.
[0032] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except the
chromium containing compound is one or more Cr.sup.+2 compounds
which react with hydroxyl groups on the surface of the catalyst
support gel. Such Cr.sup.+2 compounds are exemplified by the
formula R.sup.b.sub.2Cr where R.sup.b is a substituted or
unsubstituted indenyl or cyclopentadienyl and wherein the two
R.sup.b groups may be the same or different groups. Exemplary
Cr.sup.+2 compounds include bis-cyclopentdienylchromium;
bis-indenylchromium; and
bis-pentamethycyclopentadienylchromium.
Transition Metal Catalyst Component
[0033] Transition metal catalyst components useful in embodiments
of the invention include those activated by methylalumoxane (MAO)
and isobutylalumoxane (IBAO) and disclosed in U.S. Patent
Application Publication No. 20020107342, the disclosure of which is
hereby incorporated by reference.
[0034] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except the
transition metal catalyst component is represented by the formula,
formula 1:
##STR00001##
wherein Ph indicates phenyl.
[0035] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except the
transition metal catalyst component is represented by the following
formula, formula 2:
##STR00002##
[0036] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except the
transition metal catalyst component comprises one or more active
metals selected from the group consisting Zr, Hf, and Ti.
Binders
[0037] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except that one
or more binders are added to the catalyst support gel, chromium
containing compound and transition metal compound. Binders may be
added as a means of improving the catalyst support gel morphology,
i.e. narrowing the particle size distribution, lower porosity of
the particles and allowing for a reduced quantity of alumoxane,
which is acting as a `binder.` The binder should be soluble in
aromatic solvent and inert to the active catalyst components. In a
particular embodiment, the one or more binders which are soluble in
aromatic solvents and which are selected from the group consisting
of methylalumoxane, polystyrene, polystyrene-ethylene copolymer,
polysytrene allyl alcohol copolymers, polyvinylchloride,
polyisoprene, polybutadiene, partially hydrogenated polyisoprene,
modified methylalumoxane, polyvinylacetate, isobutylalumoxane, and
trialkylaluminum compounds having the formula AlR.sub.3 where each
R is selected from the group consisting of saturated alkyls having
less than twelve carbon atoms.
[0038] Other binder materials, soluble in the suspension solvent
and that are inert to the catalytic components may be used.
Polymerization Reaction Systems Useful with the Catalysts
[0039] Catalysts prepared in accordance with the embodiments of the
inventive process may be used in producing polyethylene in any
known polymerization system. Exemplary polymerization systems
include gas phase and slurry polymerization systems. Exemplary
slurry reaction systems include those using loop reactors (as
described in U.S. Patent Application Publication Nos. 20030012705,
20030023010, and 20030027944, European Patent 1195388 and PCT
Application Publication No. WO2004094489, the disclosures of which
are incorporated herein by reference) or stirred tank reactors (as
described in PCT Application Publication No. WO2003016362, the
disclosure of which is incorporated herein by reference). Exemplary
gas phase polymerization systems include those described in U.S.
Pat. Nos. 6,187,866; 6,846,886 and 6,617,405, the disclosures of
which are incorporated herein by reference.
Catalyst Support Gel Treatment
[0040] The catalyst support gel treatment process includes two
distinct procedures. The first such procedure is calcination. The
catalyst support gel is calcined in either air or an inert gas. Due
to the small particle size of the catalyst support gel, a rotary
kiln is preferably used. The particles are continuously agitated
while heated to prevent agglomeration. A batch kiln is preferred,
although continuous plug flow kilns are also acceptable.
Calcination occurs at a temperature of greater than 300.degree. C.
to up to the sintering temperature of the catalyst support gels. In
general, the calcination temperature ranges from 350 to 900.degree.
C. If the chromium containing compound used is one which must be
oxidized to a Cr.sup.+6valence state, air or oxygen is preferably
used as the heating gas. The catalyst support gel may subsequently
be cooled under an inert gas, such as nitrogen, to a temperature
less than 300.degree. C.
[0041] The catalyst support gel is further impregnated with a
chromium containing compound. The impregnation process may be
conducted in either an aqueous or non-aqueous environment. In
aqueous impregnation, the catalyst support gel is slurried in water
at a neutral pH. Sufficient water soluble chromium containing
compound is added to provide the desired amount of chromium in the
catalyst particles. Following aqueous impregnation, the catalyst
support gel may be calcined or otherwise dried at a temperature
sufficient to remove water. Typically, a drying temperature of
about 150.degree. C. is used. In non-aqueous impregnation, the
catalyst support gel is calcined or otherwise dried at a
temperature sufficient to remove any adsorbed water. Typically, a
drying temperature of about 150.degree. C. is used. The catalyst
support gel is then dispersed in a non-aqueous solvent. Exemplary
non-aqueous solvents include alkyl alcohols, such as methanol to
form a catalyst support gel slurry. Certain organochromium
compounds exemplified by bis cyclopentadienyl chromium that are
soluble in aromatic solvents may also be used. The chromium
containing compound is then added to the catalyst support gel
slurry and the solvent may subsequently be evaporated or otherwise
removed. Optionally, adjuvants, such as titanate esters, may be
added during the impregnation process. If an aromatic solvent is
used the solvent removal step is not required in all embodiments of
the invention.
Reaction of Calcined Catalyst Support Gel with Chromium Containing
Compounds
[0042] In some embodiments of the inventive process, the catalyst
support gel does not contain a chromium containing compound. In
such instances, the calcined non-chromium containing catalyst
support gel is added to a hydrocarbon solvent, such as an aliphatic
or aromatic solvent, to create a catalyst support gel slurry. A
chromium containing compound is then added to the catalyst support
gel slurry. In some embodiments, a chromate ester compound is added
such that 5 to 20 micrograms of chromium, as metal, is present per
square meter of catalyst support gel surface area. The chromate
ester is generally insoluble in the hydrocarbon solvent thereby
generally requiring a relatively long mixing time to allow the
chromate ester to deposit on the catalyst support gel surface.
Typically, the slurry is mixed for 1 to 24 hours. All individual
values and subranges from 1 to 24 hours are included herein and
disclosed herein. For example the slurry may be mixed for 1, 2, 6,
10, 14, 18, 22, or 24 hours. The chromium treated catalyst support
gel may remain in the slurry while additional components are added.
Alternatively, the solvent may be removed to provide a chromium
treated catalyst support which may be stored for subsequent
use.
Suspension in Solvent Prior to Spray Drying
[0043] Prior to the spray drying step, the chromium treated
catalyst support gel is suspended in a solvent which is free of
impurities that may react with Cr.sup.+6 species. Such impurities
include, for example, oxygen and water.
Reassembly by Spray Drying
[0044] The suspension prepared as described above containing the
chromium impregnated catalyst support gel, optional binders,
optional transition metal components and MAO or IBAO (where added
in the specific embodiment) is used as feedstock to a spray dryer.
Any known atomization system may be used. In particular
embodiments, a rotary atomizer or a pressure nozzle for atomization
may be used. Rotary atomizers are particularly preferred due to
their ability to atomize feedstocks containing solids. The atomizer
is preferably capable of generating a droplet size distribution
such that the size of the overall dried particles is in the
appropriate range for polymerization in a particle forming reactor.
For use in gas phase fluidized bed polymerization systems, the
spray dried catalyst should have a particle size, D.sub.50, from 10
to 75 microns. For use in slurry reaction systems, the spray dried
catalyst should have a particle size, D.sub.50, from 5 to 50
microns.
[0045] In certain embodiments of the inventive process, the spray
drying process produces less than 5 percent by weight very fine
catalyst particles characterized by a volume average particle size
of less than 1 micron.
[0046] In an alternative embodiment, the instant invention provides
a process for preparing a catalyst and a catalyst made thereby in
accordance with any of the preceding embodiments, except that a
closed cycle spray dryer, i.e. one in which the solvent evaporated
is condensed from the drying gas and the drying gas then recycled,
is used. U.S. Pat. No. 5,290,745, the disclosure of which is
incorporated herein by reference, describes one closed cycle spray
dryer which may be used in certain embodiments of the invention. An
open cycle spray dryer may be used, but will result in usage of
large amounts of drying gas and require a secondary means to
control the emission of the solvent vapors included in the drying
gas. Contaminants, such as water, oxygen, and carbon dioxide, are
preferably excluded from the drying gas. Generally, the drying gas
should have less than 1 ppm volume of any contaminant which is
reactive with the transition metal components in the catalyst.
[0047] Following the spray drying step, catalyst particles may be
collected using any known method. In a particular embodiment, the
catalyst particles are collected using a cyclone. The use of
cyclones also allows for the preferential exclusion of the finer
particles by tuning the design of the cyclone, i.e. changing the
minimum cut diameter. Such techniques are known in the art and are
taught, for example, in K. M. Masters, "Spray Drying."
Catalyst Feed
[0048] Catalyst prepared according to embodiments of the invention
may be fed to the polymerization reactor using a dry feed method or
as a slurry in a hydrocarbon diluent. In some instances, it is
preferred that the catalyst be dispersed in a hydrocarbon which is
a non-solvent for the binder and which is non-reactive to any of
the active catalyst components. When the catalyst is used in slurry
form, heavy hydrocarbon diluents, such as aliphatic mineral oils,
are preferred carriers because they provide protection against
rapid settling of the catalyst particles and protection against
adventitious moisture and oxygen. When used in a slurry form,
additional modification of the catalyst may be undertaken either
off-line, in batch mode, or in an in-line mode as described, for
example, in U.S. Provisional Application Nos. 60/469,663 and
60/469,665, the disclosures of which are incorporated herein by
reference.
EXAMPLES
[0049] The following examples illustrate the present invention but
are not intended to limit the scope of the invention. All of the
following examples and procedures are prophetic in nature
irrespective of the tense of the verbs used in describing such
examples and/or procedures. No comparative examples are provided
herein.
[0050] Catalyst Support Treatment
[0051] Catalyst support gels are calcined in a batch rotary kiln to
the specified temperature and for the specified duration, as
described below. In all cases, the catalyst supports are then
cooled under nitrogen prior to use in the process to prepare a
catalyst. Chromium treatment with an oxidizable chromium containing
compound is performed using one of the methods specified
previously. The conditions are given in Table 1.
TABLE-US-00001 TABLE 1 Cat. Cat. Calcine Calcine Cr Cr Loading
support Support Temp., time, Treatment (as Cr type Ex. No. .degree.
C. Hours Type* Cr Compound metal) GASIL 1 600 4 None 0 23D GASIL
114 2 600 4 None 0 GASIL 3 600 4 None 0 AB720 GASIL 4 600 4 None 0
HP285 GASIL 5 600 4 None 0 AB725 GASIL A1 150 2 Aqueous
Cr(CO.sub.2CH.sub.3).sub.3 0.5 23D Impregnation Cat. B1 750 4
Oxidation Support Ex. No. A1 GASIL 114 A2 150 2 Non-aqueous
Cr(NO.sub.3).sub.3 in 0.2 Impregnation methanol Cat. B2 750 4
Oxidation Support Ex. No. A2 GASIL A3 150 2 Non-aqueous
Cr(NO.sub.3).sub.3 in 0.2 AB720 Impregnation methanol Cat. B3 600 4
Oxidation Support Ex. No. A3 GASIL A4 150 2 Non-aqueous
Cr(NO.sub.3).sub.3 in .75 HP285 Impregnation methanol Cat. B4 750 4
Oxidation Support Ex. No. A4 GASIL A5 150 2 Aqueous
Cr(CO.sub.2CH.sub.3).sub.3 0.5 AB725 Impregnation Cat. B5 750 2
Oxidation Support Ex. No. A5 *The methods of chromium impregnation
in Table 1 are described in more detail above.
[0052] GASIL catalyst support gels are commercially available from
the PQ Corporation. Table 2 lists the physical properties of the
GASIL catalyst support gels used in Table 1.
TABLE-US-00002 TABLE 2 Cat. Cat. Pore Particle Surface Oil support
Support Volume size, area, adsorption, type Ex. No. cc/gram microns
m.sup.2/gram g/100 grams GASIL 23D 1 1.6 4.6 290 290 GASIL 114 2
1.2 6.5 320 200 GASIL 3 ~0.5 3.2 500 90 AB720 GASIL 4 1.8 8.7 280
280 HP285 GASIL 5 1 5.3 400 160 AB725
[0053] Table 3 provides the physical properties of certain catalyst
support gels prior to comminution. In Table 3, "APD" means average
pore diameter
TABLE-US-00003 TABLE 3 Average Average Cat. Pore Surface Pore
Particle Ti support volume, area, Diameter, Size, content, type
cc/g m.sup.2/g Angstrom micron % Silica Supports GRACE 955 1.62 310
210 55 -- GASIL PQ 3.02 513 198 90 -- M3050 Cogel Supports
CROSFIELD 1.15 490 104 94 2.60 EP52 GRACE 9702 2.58 444 232 153
2.30 GRACE 955 and 9702 supports are commercially available from W.
R. Grace & Co. CROSFIELD supports are commercially available
from INEOS Silicas Co. (Joliet IL).
[0054] Table 4 provides the physical properties of certain aluminum
containing catalyst support gels prior to comminution.
TABLE-US-00004 TABLE 4 Average Cat. Pore Surface Pore Cr Al support
volume, area, Diameter, content, content, type cc/g m.sup.2/g
Angstrom % % PQ C-34060MS 2.46 364 270 0.26 2.87 PQ C-34160MS 2.45
354 277 0.50 3.00 PQ C-23060 1.99 314 254 0.25 2.62 PQ C-23160 2.09
336 249 0.48 2.86
[0055] Comminution Process
[0056] The comminution can be carried out using methods known in
the art. Ball mills may be used and are particularly useful when
the support has been thermally treated (i.e. calcinations
with/without Cr compound addition). The ball milling may be done
"dry" or with solvent present. When solvent is present, it is
preferably the solvent that will be used in spray drying.
Generally, ball milling will be done dry if the support will be
later treated thermally.
[0057] An impact mill that uses a rotor to mechanically accelerate
the feedstock into stationary blocks may also be used. The material
shatters when impacting the stationary blocks. The shattered
material is air or nitrogen swept out of the mill housing and into
a cyclone. The cyclone can be adjusted, along with the gas flow, to
cause dust (sub-micron particles) to be rejected and the larger
particles retained in the cyclone. This operation may take place
before or after any thermal treatment.
[0058] Fluid energy mills, in which particle to particle collisions
result in size reduction, may also be used. Fluid energy mills are
typically used in the pharmaceutical industry and can result in
relatively narrow particle size distributions of the resultant
comminuted solid.
[0059] Other mills may also be used, however these are well known
in the art and render the final particles useful directly in the
next step, i.e. the catalyst assembly by spray drying.
[0060] Preparation for Spray Drying
[0061] Typical reassembly by spray drying is conducted in the
following manner: 1. Add the desired amount of toluene to the mix
vessel; 2. Add the calcined, chromium impregnated catalyst support
gel to the solvent while mixing; 3. Add polymeric binder; 4. Charge
the desired quantity of MAO to the slurry feed vessel; 5. Charge
the metallocene/non-metallocene catalyst components that are
activated by MAO; and 6. Mix to disperse at 35.degree. C. and spray
dry. Table 5 provides the condition to use in preparing the spray
dryer feedstock.
[0062] The solids content of the spray drying feedstock is adjusted
to maintain 10 to 35 wt % solids in the feed. Table 5 provides a
formulation for a typical slurry spray dryer feedstock.
TABLE-US-00005 TABLE 5 Material Function Amount Toluene Solvent
20.0 kg 30% MAO in toluene Binder and 9.5 kg activator Bis
dibenzylzirconiumamide Catalyst 110 grams n-propylcyclopentadienyl,
Metallocene: 9.5 grams tetramethylcyclopentidienylzir- catalyst
conium dichloride Calcined, chromium containing Catalyst 2.8 kg
catalyst support gel
[0063] Spray Drying
[0064] The spray dryer is operated in a closed cycle mode using a
packed column with counter current chilled solvent as a scrubber. A
rotary atomizer with a 120 mm diameter wheel and four or eight
nozzles is used. Maximum atomizer speed is 24,000 RPM. Atomizer
speed is adjusted to control final dry particle size. Nitrogen is
the drying gas. For these examples, a 4 foot diameter Niro spray
dryer is used. The particular spray dryer has a recycle gas flow
rate that normally ranges between 250 and 650 pounds/hour. Higher
cycle gas flow rate allows for higher outlet temperature from the
dryer. Lower flow rates increase the residence time in the dryer.
Both can affect the final particle properties. Inlet temperature is
adjusted using a steam heated exchanger. The inlet temperature is
controlled to maintain a fixed outlet temperature. There is no
specific upper limit on the inlet temperature. The outlet
temperature is adjusted such that the particles dry effectively and
at a level such that the catalyst is not damaged by excess heat.
Typical outlet temperatures range from 70 to 120.degree. C. For
catalysts using polymeric binders, the outlet temperature is
sufficiently low such that the sticking temperature of the polymer
is not exceeded. The scrubber outlet temperature is controlled to
control the dewpoint of the drying gas. Typical values of -5 to
+10.degree. C. are used. Atomizer speed is adjusted to control
particle size to the desired range. A typical range is between 50
and 100% of maximum speed. The inlet and outlet temperatures are
the primary controls for residual solvent content; the scrubber
outlet temperature affects the initial drying rate of the droplets
and the atomizer speed controls the droplet size. The atomizer feed
rate affects the heat balance and has some effect on the final
particle size with higher feed rates giving larger particle size.
The above described spray dryer is used to produce the following
examples of catalyst prepared in accordance with the invention.
Typical recovery of solids from the spray drying operation is
greater than 90% by weight. Table 6 provides the materials to be
used in preparing the spray dryer feedstock to prepare Catalyst
Examples 1 and 2.
TABLE-US-00006 TABLE 6 MATERIAL Catalyst Examples 1 and 2 Feedstock
Preparation Charge wt. in kg Toluene 16.99 30% MAO in Toluene 8.11
E- Metallocene MAO Solution 0.303 (24.4 wt % in Toluene Catalyst
support Ex. B1 2.4
[0065] The feedstock is prepared with a desired Al/Zr ratio of 245
and a Zr loading of 33.3 micromoles/gram dried solids. The Cr
content of the dried catalyst is 0.25 wt %. Spray drying conditions
are given in Table 9.
[0066] Table 7 provides the materials to be used in preparing the
spray dryer feedstock to prepare Catalyst Examples 3 and 4.
TABLE-US-00007 TABLE 7 MATERIAL Catalyst Examples 3 and 4 Feedstock
Preparation Charge wt. in kg. Toluene 17.29 30% MAO in Toluene 8.09
HN3--Zr 0.11 Catalyst Support Ex. B5 1.11 Catalyst Support Ex. B4
1.1
[0067] The feedstock is prepared with a desired Al/Zr mole ratio of
231 and a Zr loading of 50 micromoles/gram dried solids. The Cr
Content of the dried catalyst is 0.33 wt %.
[0068] Table 8 provides the materials to be used in preparing the
spray dryer feedstock to prepare Catalyst Examples 5 and 6.
TABLE-US-00008 TABLE 8 MATERIAL Catalyst Example 5 and 6 Feedstock
Preparation Charge wt. in kg. Toluene 11.73 30% MAO in Toluene 5.22
HN.sub.3--Zr 0.10 Catalyst Support Ex. B5 0.48 Catalyst Support Ex.
B4 0.48
[0069] The feedstock is prepared with a desired Al/Zr mole ratio of
171. The Zr loading was 50 micromoles/gram dried solids. Cab-O-Sil
TS 610 is added as a filler. The final Cr loading was 0.25 wt
%.
[0070] Spray drying conditions for Catalyst Examples 1-6 are given
in Table 9. In Table 9, all temperatures are given in C.degree. .
100% atomizer speed is 24,000 RPM. Oxygen values are those at the
beginning of the spray drying run. Generally, this value goes to
zero within 1 to 3 kg of feed. Feed rate is in pounds/hour. Drying
gas flows are also measured in pounds/hour. A portion of the spray
dryer cycle gas bypasses the drying chamber. This serves to improve
temperature control. Alternately, the cycle gas blowers can be
individually adjusted for flow rate.
TABLE-US-00009 TABLE 9 Cat. Cat. Cat. Cat. Ex 1 Ex. 2 Ex. 3 Ex. 4
Cat. Ex. 5 Cat. Ex. 6 Inlet Temp 150 140.5 150 150 150 150 Outlet
Temp (RTD) 98.4 98.5 92 93 108 105.3 Atomizer % 70 95 70 95 95 70
Oxygen ppm 1 1 5 5 10 10 Feed Rate lb/hr 30 30 38-42 38-42 40 40
Drying Gas Flow 416 419 427 434 605 603 Condenser out -6 -6 -6 -6
-6 -6
[0071] The condenser outlet temperature is the temperature of the
gas exiting the scrubber condenser. The actual liquid in the
condenser is, of course, lower.
[0072] The structures of X metallocene and E metallocene are given
in Formulas 1 and 2, respectively.
[0073] Table 10 provides the materials to be used in preparing the
spray dryer feedstock to prepare Catalyst Examples 7 and 8.
TABLE-US-00010 TABLE 10 MATERIAL Catalyst Example 7 and 8 Feedstock
Preparation Actual Toluene 16.99 30% MAO in Toluene 8.11 E-
Metallocene MAO Solution 0.303 (24.4 wt % in Toluene) HN-3 Zr 0.11
Catalyst Support Ex. 1 2.4 Silyl Chromate 0.012
[0074] The feedstock is prepared with a desired Al/Zr ratio of 245
and a Zr loading of 33.3 micromoles/gram dried solids. The Cr
content of the dried catalyst is 0.25 wt %.
[0075] Table 11 provides the materials to be used in preparing the
spray dryer feedstock to prepare Catalyst Examples 9 and 10.
TABLE-US-00011 TABLE 11 MATERIAL Catalyst Examples 9 and 10
Feedstock Preparation Charge wt. in kg. Toluene 17.29 E metallocene
30% MAO 8.09 in Toluene HN3--Zr 0.11 Silyl Chromate 0.012 Catalyst
Support Ex. 1 1.11 Catalyst Support Ex. 2 1.1
[0076] The feedstock is prepared with a desired Al/Zr mole ratio of
231 and a Zr loading of 50 micromoles/gram dried solids. The Cr
Content of the dried catalyst is 0.25 wt %
[0077] Table 12 provides the materials to be used in preparing the
spray dryer feedstock to prepare Catalyst Examples 11 and 12.
TABLE-US-00012 TABLE 12 MATERIAL Catalyst Example 11 and 12
Feedstock Preparation Charge wt. in kg. Toluene 11.73 E metallocene
30% MAO 5.22 in Toluene HN3--Zr 0.10 Cab-O-Sil 0.52 Gel Particle 5
0.48 Catalyst support Ex. 4 0.48 Silyl Chromate 0.006
[0078] The feedstock is prepared with an aim Al/Zr mole ratio of
171. The Zr loading is 50 micromoles/gram dried solids. Cab-O-Sil
TS 610 is added as a filler. The final Cr loading is 0.2 wt %.
Table 13 provides the spray drying conditions for Catalyst Examples
7-12.
TABLE-US-00013 TABLE 13 Cat. Cat. Cat. Ex. Cat. Ex. Cat. Ex. Ex. 7
Ex. 8 Cat. Ex. 9 10 11 12 Inlet Temp 150 140.5 150 150 150 150
Outlet Temp 98.4 98.5 92 93 108 105.3 (RTD) Atomizer % 70 95 70 95
95 70 Oxygen ppm 1 1 ND 5 ND 10 Feed Rate lb/hr 30 30 38-42 38-42
40 40 Drying Gas Flow 416 419 427 434 605 603 Condenser out -6 -6
-6 -6 -6 -6
[0079] Table 14 provides the materials to be used in preparing the
spray dryer feedstock to prepare Catalyst Example 13.
TABLE-US-00014 TABLE 14 MATERIAL Catalyst Example 13 Feedstock
Preparation Charge wt. in kg. Toluene 17.29 30% MAO in Toluene 8.09
HN3--Zr 0.11 Catalyst Support Ex. B4 2.2
[0080] The feedstock is prepared with an aim Al/Zr mole ratio of
231 and a Zr loading of 50 micromoles/gram dried solids. The Cr
Content of the dried catalyst is 0.35 wt %.
[0081] Blends were made simulating the performance of the catalysts
described above. Catalysts Example 7 produce polymer with a size
exclusion chromatogram which is depicted in FIG. 1. In FIG. 1, the
solid line indicates polymer produced using silyl chromate
catalyst, the dashed 1 line indicates polymer produced using
catalyst example 7 and the dashed double dotted line indicates
polymer produced using a dual reactor.
* * * * *